Conduit



May 18; 1937.

P. T. COONEY CONDUIT 7 Filed Aug. 8, 1935 Patented May 18, 1937 UNITED STATES PATENT OFFICE This invention relates to conduits, and has to do with conduits constructed of concrete or analogous material.

One of the main objects of my invention is to.

provide a conduit of improved construction, which can be readily constructed at relatively low cost and possesses adequate strength while being free of all joints or openings other than necessary expansion joints. More specifically, it is an object of my invention to provide a conduit comprising an inner liner composed of sections which can be readily handled and placed, and an outer continuous shell cast about the inner liner as a permanent inner form for the shell, this shell possessing adequate strength and being free of joints or other openings. Further objects and advantages of my invention will appear from the detailed description.

In the drawing:

Figure 1 is a vertical transverse sectional view through a conduit embodying my invention;

Figure 2 is a fragmentary sectional view taken substantially in the plane of line 22 of Figure 1;

Figure 3 is a perspective side View, partly in section and with parts removed, of a modified form of conduit embodying my invention showing the method of construction thereof;

Figure 4 is a transverse sectional view through a second modified form of conduit embodying my invention, this figure being on a larger scale than Figure 3; and

Figure 5 is a transverse vertical sectional view through a third modified form of conduit embodying my invention.

Referring to Figures 1 and 2, the conduit comprises an inner liner formed of precast concrete sections I. These sections are of semi-cylindrical shape and are disposed one upon another so as to define the interior of the conduit which, in

this instance, is shown as of circular cross-section. The inner liner sections I may be cast of Portland cement grout consisting of fine sand and an appropriate amount of cement depending upon the voids in the sand. In casting the liner sections the inner forms used therefor have smooth surfaces of such a character that the inside suriace of the liner sections will have a low coeflicient of friction, which is conducive to ready flow of fluid through the conduit.

In constructing the conduit, after the trench has been excavated to subgrade a sufiicient amount of concrete is placed to form the base portion 2a of an outer shell which is to enclose the liner. Reenforcing rods 3 are placed within base portion 2a above suitable tie wires 4 which are also placed in the base portion, during formation thereof. The lower liner sections are then set to grade and are bedded in the base portion 2a. This is done before the concrete of the base portion takes its set so that the lower liner sections can be placed with accuracy and facility and the upper surface of the base portion 2a is shaped to conform to the lower liner sections. The upper liner sections are placed upon the lower sections so as to define therewith the interior of the conduit, the end joints between the sections I being broken or spaced apart as shown a wires being twisted or otherwise suitably secured together. The wires 4 and blocks 5 cooperate to anchor the liner to' base portion 2a of the outer shell and to hold the sections of the liner in their proper relative positions. The main or body portion 2b of the outer shell 2 is then cast about the inner liner as a permanent inner form for the shell, it being understood that in this operation suitable outer forms are disposed about the liner in proper relation thereto in a known manner.

The outer shell 2 is of continuous construction there being no joints present with the exception that suitable expansion joints may be provided as required. Each length of the conduit, between expansion joints, comprises the inner liner which remains in place and. defines the interior of the conduit and the outer shell which is of continuous construction and forms a unitary structure with the inner liner.

. Preferably the inner liner sections l are suitably reenforced, as by means of wire mesh 6. Since the liner sections need be only strong enough to withstand safely handling and the pressure exerted by the material of the outer shell during pouring of the latter, the liner sections may be of relatively thin construction. This is advantageous in that it renders these sections suificiently light in weight to be handled and transported with facility. In this connection, the use of the wire mesh reenforcement for the liner sections is advantageous, and is preferred, although it is not essential .in all cases. The method of construction, in which the inner liner forms 'the permanent inner .mold for casting of the outer shell, in many instances, as where ade quate supplies of sand and gravel aggregate are available at or near thesite, saves transportation of large quantities of materials for consid-. erable distances and thus eiTects a corresponding saving in the construction of the conduit. The shell 2 may be of adequate strength in accordance with requirements and, being free of joints, efiectively eliminates possibility of roots and like growths entering the conduit with injurious effects thereto.

Where desired or necessary, the outer shell of the conduit may be additionally reenforced.

Also, if desired, the inner liner may be provided with an outer coating of water-proofing material effective to prevent water from, penetrating the outer shell. In Figure 4 the outer shell of the conduit is designated 7 and comprises abase portion la and a body portion 117. In constructing this conduit a steel reenforcing member 8, which may be in the form of a spiral, is em'-" bedded in base portion 1a ofthe shell with its convolutions extending above the inner liner in substantially concentric spaced relation thereto, the sections of the liner being disposed within the convolutions of the reenforcing member dur ing assembly of the liner. The outer surface of the liner sections may be provided with a coating 9 of a suitable water-proofing material, preliminary to placing of the liner sections. The remainder or body portion of shell 1 is then cast above the inner liner as a permanent inner form, the shell enclosing the reenforcing member 8 with which may be associated, if desired, re-

enforcing steel rods l extending lengthwise of the liner within the convolutions of reenforcing member 8, the rods ID, if used, also being enclosed within the shell I.

The conduit illustrated in Figure 3 is similar to that of Figure 4 except that the coating 9 of water-proofing material, of the latter figure, is omitted. Referring to Figure 3, after the lower portion tof trench T has been excavated to subgrade, a sufficient amount ofv concrete is placed to form the base portion la of the shell 1. The liner is then assembled, within the convolutions of reenforcing member a which, as will be understood, has previously been placed and is partially embedded within the section 10.. Reenforcing rods H) are then placed within the convolutions of member 8 so as to extend lengthwise of the liner and, preferably, concrete blocks 5. are inserted between rods l0 and the liner sections l, these blocks cooperating with rods l0 and member 8 for securing the liner sections I in position. The main or body portion lbof shell 1 is then cast about the inner liner as a permanent inner mold, in the manner previously described.

Certain substances, such as sewageand' various gases, may have a tendency to attack concrete.

7 composed of sections of suitable lengths. In

this form of conduit each section of the liner is of approximately semi-elliptical shape in cross- 7 section and corresponds to the interior cross-sectional form. of the conduit. Each liner section llv comprises an outer or body portion [2 which may be formed of concrete and provided with a wire mesh reenforcing element [3, as above described. The body l2 is provided with an inner facing comprising a plurality of blocks 14 of vitrified clay or other suitable material. The inner edges of these blocks are disposed substantially in contact, as shown, with the adjacent side faces of the blocks diverging outward and defining a substantially V-shaped space which is filled with a'sealing compound I resistant to the substance conducted by the conduit. Conveniently each of the blocks I4 is recessed from its outer face, at l6, and the material of body I 2 of section II extends into this recess, the blocks l4 being thus secured to body l2 so as to form a unitary structure therewith. In casting each of the sections H, blocks M are suitably assembled in the mold, with the spaces between the blocks filled by the sealing compound is first placed, this base portion being shaped as shown. The liner sections II are then placed upon the base portion within reenforcing members I8 suitably anchored in the base portion I'm, in which may be disposed reenforcing rods l9. and 20. Reenforcing rods 2! may be disposed lengthwise of the liner section, between the latter and reenforcing members [8, members l8 and rods 2|. cooperating to secure the liner sections in position. The main or body portion Nb of shell I l is then cast above the inner liner as a. permanent inner mold, thus completing the conduit.

In the various figures of the drawing I have shown the base portion and the bodyportion of the outer shell of the conduit as separated by lines indicating the joints between these two portions. In practice, however, the portions of the shell will be bonded together, as is known, to form a monolithic structure of great strength. It will also be understood that the cross-sectional shape of the conduit may assume various forms. In Figures 1, to 4, inclusive, the interior of the, conduit is of circular cross-section, the inner liner sections being of semi-cylindrical shape. The shape of the liner sections will depend upon the interior cross-sectional shape of the conduit, as will be understood but, in general, will approximate onehalf of the interior cross-sectional shape of the conduit in instances where the liner sections define the interior of the conduit. In cases where the conduit is of approximately semi-elliptical interior cross-section, as in Figure 5, the liner sections may be of similar cross-section, the bottom or base of the interior of the conduit being defined by the upper surface of the base portion of the outer shell, which upper surface of thisbase portion may be' suitably shaped for this purpose.

As above indicated, and as will be understood by those skilled in the art, variations in the construction and arrangement ofparts may'be resorted to without departing from the field and scope of my invention, and, I intend to. include allsuch variations, as fall within thescope or the appended claims, in this applicationinfwhich the preferred forms only of my. invention are disclosed.

What I claim is:-'

1. In combination, in a conduit of the character described, an inner liner comprising monolithic precast sections each approximately conforming in cross-section to one-half of the interior cross-section of the conduit, said sections being laid in lengthwise overlapping relation with the joints between the ends of sections spaced apart and each section extending across and reinforcing the joint between the two next adjacent cooperating sections, an outer shell comprising a base portion in which the lower portion of the liner is bedded and a body portion extending from the said base portion and enclosing said liner, spacing blocks disposed about the liner in contact therewith, and tie wires anchored in said base portion of the shell and secured about said blocks and cooperating with the latter for holding said liner sections in position, said shell being cast about said liner as a permanent inner form for said shell and enclosing said wires and blocks, said inner liner remaining in place and the inner surface thereof constituting the permanent inner surface of the conduit, said shell being continuous and free of joints throughout its length.

2. In combination, in a conduit of the character described, an inner liner comprising monolithic precast sections each approximately conforming in cross-section to one-half of the interior cross-section of the conduit, said sections being laid in lengthwise overlapping relation with the joints between the ends of sections spaced apart and each section extending across and reinforcing the joint between the two next adjacent cooperating sections, an outer shell comprising a base portion in which the lower portion of the liner is bedded and a body portion extending from the said base portion and enclosing said liner, spacing blocks disposed about the liner in contact therewith, reenforcing rods embedded in and extending lengthwise of said base portion, and tie wires extending beneath said rods and secured about said blocks and cooperating with the latter for holding said liner sections in position, said shell being cast about said liner as apermanent inner form for said shell and enclosing said wires and blocks, said inner liner remaining in place and the inner surface thereof constituting the permanent inner surface of the conduit, said shell being continuous and free of joints throughout its length.

3. In combination in a conduit of the character described, an inner liner comprising opposed upper and lower monolithic precast sections each of approximately semi-circular cross-section, the upper sections seating upon the lower sections and being sustained in position thereby, said sections being laid in lengthwise overlapping relation with the joints between the ends of sections spaced apart and each section extending across and. reinforcing the end joint between the two next adjacent cooperating sections, an outer monolithic shell comprising a base portion in which the lower portion of the liner is bedded and a body portion extending from said base portion and enclosing said liner, spacing blocks spaced about the liner in contact therewith, and tie wires anchored in said base portion of said shell and secured about said blocks and cooperating therewith for securing said liner sections in position, said shell being cast about said liner as a permanent inner form for said shell and enclosing said wires and blocks.

4. In combination in a conduit of the character described, an inner liner comprising opposed upper and lower monolithic precast sections each approximately conforming in cross-section to one-half of the interior cross-section of the conduit, the upper sections seating upon the lower sections and being sustained in position thereby, said sections being laid in lengthwise overlapping relation with the joints between the ends of sections spaced apart and each section extending across and reinforcing the end joint between the two next adjacent cooperating sections, an outer monolithic shell comprising a base portion in which the lower portion of the liner is bedded and a body portion enclosing said liner, said body portion being poured about the remainder of the liner and said shell being cast about said liner as a permanent inner form for said shell,

and means anchored in said base portion and securing the liner thereto effective for retaining said liner sections in proper relation to each other and the base portion during pouring of said body portion of said shell.

5. In combination in a conduit of the character described, an inner liner comprising mono- PAUL T. COONEY. 

